Re: recursive cache expanding bug

[Gregor.pa@Xerox.COM]

    Date: Tue, 20 Jun 89 15:54:20 -0400
    From: kanderso@DINO.BBN.COM

    1.  Fixed a bug in ENSURE-GENERIC-FUNCTION-CACHE that throws away a
    cache that has just grown because it was too big, so gf's grow and
    then shrink as they are invalidated and used.

I installed this change.

    2.  Suppose something calls CLASS-DIRECT-SUBCLASSES,
    EXPAND-DCODE-CACHE is called to expand the cache of
    CLASS-DIRECT-SUBCLASSES and either GENERIC-FUNCTION-CACHE or
    SLOT-VALUE-USING-CLASS are invalidated.  Then the innocent looking
    line

    (Is this really another cache locking issue?)

Sort of, it also resembles the metacircularity issues of having to call
a generic function as part of updating that same generic function.  I
didn't install this change, but when I rewrite the dcode mechanism to
use the new LAP stuff I will put in a *expansions-on-stack* sort of
thing to prevent this from happening.

Thanks for these bug reports and fixes.
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